The invention relates to gas turbine engines, and more particularly to blade outer air seals (BOAS) for gas turbine engines.
A gas turbine engine ignites compressed air and fuel to create a flow of hot combustion gases to drive multiple stages of turbine blades. The turbine blades extract energy from the flow of hot combustion gases to drive a rotor. The turbine rotor drives a fan to provide thrust and drives a compressor to provide a flow of compressed air. Vanes interspersed between the multiple stages of turbine blades align the flow of hot combustion gases for an efficient attack angle on the turbine blades.
The BOAS as well as turbine vanes are exposed to high-temperature combustion gases and must be cooled to extend their useful lives. Cooling air is typically taken from the flow of compressed air. Therefore, some of the energy extracted from the flow of combustion gases must be expended to provide the compressed air used to cool the BOAS as well as the turbine vanes. Energy expended on compressing air used for cooling the BOAS and turbine vanes is not available to produce thrust. Improvements in the efficient use of compressed air for cooling the BOAS and turbine vanes can improve the overall efficiency of the turbine engine.